In a large skillet, heat oil over medium-high heat. Add ground meat, sprinkle with salt and pepper and cook until the meat gets nice and golden brown, 10 to 12 minutes. With a slotted spoon, remove the meat and reserve. Lower the heat to medium and sauté ½ minced red onion in the juices until soft, about 5 minutes. Add oregano and garlic and cook until fragrant. Season. Add tomato paste and cook until it caramelizes. Deglaze and scrape any bits up that have adhered to the pan. Add the meat back in, stir and keep warm.